What are the characteristics of a deep learning AI?
As you can see from the picture above (In courtesy to this guy post). Deep learning is a field inside machine learning which involves using deep neural networks to solve machine learning problems. 

Tensorflow.js and Brain.js are software architectures built in order to assemble and develop ML models inside the browser. 

If you would like to delve into this field of deep neural networks you should start from the theory to really understand why we are using neural networks to solve problems and which problems they are intended to solve. 

You can start with this awesome video by 3blue1brown : Intro video

And this standford class for CNN: Stanford class